The objective of this study is to develop a toxicological screening test for neurotoxins using the nematode Caenorhabditis elegans as a test species. The test organism will be exposed to selected chemicals that are known to cause human neurological disorders (including organophosphate and organochlorine pesticides, organic solvents, and metals). Behavioral parameters such as rate of movement, frequency of change of direction, rapidity of response to a sensory stimulus, strength of response and rate of adaptation will be evaluated using a video camera-computer tracking system. The reversibility of these effects after removal of the chemical will be determined and all of the responses of the exposed animals will be compared to control cultures. The effects of these chemicals on growth and reproduction will be determined in parallel experiments to determine the relative sensitivity of the different types of end points. The overall goal is to develop a test that can be used to rapidly and inexpensively screen a large number of chemicals so more elaborate testing can be focused on substances with the most potential neurotoxicity.